Buttonhole-sewing machine



A. HENNlG BUTTO NHOLE SEWING MACHINE April 28, 11925.

5 Sheets-Sheet 1 Filed Feb. 14, 1925 IN l/E/V 719R Fig.1

%m N E N N M W 7; f A 5 um April 28, 19 25. 1,536j002 A.'HENNIG BUTTONHOLE SEWING MACHINE Filed Feb. 14, 1925 5 Sheets-Sheet 5 uvv/v roe 14L BEET' HENN/G ATIfbR/VE. Y5

April '28, 1925. 1,536,002

' A. ,HENNIG B UTTONHOLE SEWING MACHINE Filed Feb. 14, 1925 5 Sheets-Sheet 4 INVENT'UR HLBERT Mew/W6 ATTORNE Y5 April 28, 1925. 1,536,002

A. HENNlG BUTTQNHOLE SEWING MACHINE Filed Feb. 14, 1925 5 Sheets-Sheet 5 IN VE N T 0/2 ALBERT Havana ATTORNEYJ Patented Apr, 28, 1925.

UNITED STATES PATENT OFFICE.

ALBERT HENNIG, 0F BIELEFELD, GER-MANY, ASSIGNOR TO ANKER-WERK .AKTIENGESELLSCHAF'I, 0F BIELEFELID,-GERMANY.

BUTTONHOLE-SEWING MACHINE.

Application filed February 14, 1925. Serial No. 9,246.

To all whom it may concern:

1 Be it knownthat I, ALBERT 'HENNIG, a citizen of Germany, residing at Metzerstrasse 5, Bielefeld, Germany, have invented certain new and useful Improvements in Buttonhole-Sewing Machines (for which I have filed applications in Germany. on July 3, 1923, and in Great Britain on November 18, 1924) and I do hereby declare the following to bee full, clear, and exact description of the invention.

Thisinvention relates to a button hole sewing machine in which the movement of the device which feeds the material forwards is automatically reduced during the stitching of the bar, so that the stitches of the bar lie closer together than do the stitches which surround the edges of the button hole. j

According to the present invention, this is accomplished by interposing in the system of levers which operate the cam controlling the advance of the material a transmitting lever, the lever-arm of which is automatically diminished during the formation of the bar. This variation of the lever-arm is effected by a two-part cam, each part of which can be rotated relatively to the other part, whereby the effective length of the cam may be varied, the result being a corresponding variation in the length of the bar. In order to enable the number of stitches in the bar to be still further varied, the cam is: caused to actuate theadjustable lever of the system of operating rods througha bell crank lever, the fulcrum of which canbe moved by means of an eccentric whereby the position of the bell crank lever in relation to. the cam and to the adjustable lever is varied, the result being a corresponding variation of the effective lever-arm.

A constructional form of a button hole sewing machine of the type herein referred to is shown in the accompanying drawings, wherein: f Figure 1 is a plan view.

Figure 2 is a side elevational view.

Figure 3 is a top plan View of the controlling cam and Figure 4 is avertical transverse. section through the arm of the machine.

Figure 5 shows, inside elevation, the cam which produces the stitching of the bar.

ed to the frame of the machine.

Figure 6 shows the cam adjusted for a short bar and also a diagrammatic repre sentation of this bar.

Figure 7 shows the cam adjusted fora 'lojilitg bar and also a diagram of the bar itso t Figure Sshowson a larger scale a horizontal section through the adjustable transmitxting lever mechanism and also a diagram of the normal stitch.

Figures 9 to 13 are similar views illus trating different positions of the bell crank leverwhich acts on the transmitting lever, together-with the corresponding formations of the stitch.

Figure 1 1 shows separately the eccentric for the adjustment of the'bell crank lever.

The driving shaft?) is mounted in the well known way in the arm 2 of the machine which is carried on the base plate 1. On this shaft is fixed an eccentric 4, the connecting rod '5 of which is attached to an oscillating crank disc 6, which is mounted for rotary movement'in a slide 8 adapted to move longitudinally on horizontal guide bars 9 (see Figures 1 and A slide block 11 moves longitudinally in a slot 10 in this disc and is pivotally connected to a link 12 pivot- To the link 12 is attached theupper end of a connecting rod 13, which is connected to a bell crank lever 14:,mounted on the base plate 1. The other arm of this bell crank lever is con nected by a ball and socket joint 16 to a connecting rod 15 (see Figure 1), which is movab-ly engaged with a slotted lever arm 17 which is carried on the lower end of the vertical shaft 27. This slotted lever arm acts in the well known way on two feed arms 19 which grip the periphery of the feedcont'rol cam 18 and are biased byspring levers 20. When the slot-ted lever arm 17 is oscillated by the eccentric 1 on the shaft 3 the feed-control cam is advanced with a step by step motion.

On its upper side the control cam 18 is provided, in the wellknown way, with two Figure 1), while the second cam groove 22 controls the transverse movement of said work-holder by means of the connecting rod 26.

The extent of the feeding movement which the control cam 18 makes each time is regulated by shifting the crank disc 6, which acts as a transmitting lever between the connecting rods 5 and 13, relatively to the slide block 11 which itself is held by the link 12. This shifting of the crank disc is controlled by the cam 28 mounted on the vertical shaft 27. This cam consists of two superimposed similar parts each with two arms 36 and 37. The two parts can be rotated relatively to each other and then secured by means of a nut, so that the effective or real length of the cams 36 and 37 can be varied as shown in Figures 6 and 7. Against the cam 28, under the action of a spring 31 (see Figure 8), bears the roller 30 ot' a bell crank lever 29, which is pivotally mounted on an eccentric 33, manually ro tatable on a pin 34. The free, hooked end 35 of the bell crank lever 29 bears against the slide 8 in which the crank disc 6 is rotatably mounted. A compression spring 7 (see Figure 8), mounted on a guide bar tends constantly to press the slide against the end of the bell crank lever 29.

When the roller 30 bears against the lower outside edge of the cam 28, as shown in Figure 8, the feed-control cam 18 is advanced in the normal way and one edge of the button hole is stitched, as shown diagrammatically in Figure 8. When the cam 36 is brought into contact with the bell crank lever 29 (see Figure 9), by the progressive rotation of the shaft 27, a rotarymotion is imparted to said lever, the end 35 of which then moves the slide 8 towards the slideblock 11, against the action of the spring 7 (i. e., to the right in Fig. 4), so that the lever arm between the lower end of the connecting rod 5 and the upper end of the connecting rod 13 is reduced. The feed move ment of the.fced-control cam 18 is thus correspondingly reduced and, as a transverse movement of the work holder is simultaneously effected by the cam 22, through the medium of the connecting rod 26, the bar is formed at the end of the button hole, the stitches thereof lying closer together than do the stitches on the longitudinal sides of the button hole. hen the roller 30 drops off the cam 36, as the latter continues to rotate, the slide 8 is again forced back into its original position by the spring 7, and as the transverse movement of the work holder also takes place again simultaneously, the other edge of the button hole is bound with stitching until the roller or bowl 30 is again raised by the second cam 37 on the disc, after which the formation of the bar at the front end of the button hole is proceeded with.

13y rotating the two parts of the cam 28 relatively to each other, the effective length of the cams and consequently the number of close stitches of the button hole can be varied, as is shown in the diagrams of the stitches included in Figures 6 and 7.

The greater length of the cam 37 as compared with the cam 36 is for the purpose of ensuring that the stitches at the edge of the new button hole shall lie closer together at the very beginning than they do at the other part of the marginal stitching, in order to ensure the button hole being efficiently closed. If both the cams 36 and 37 were of the same length the normal rate of feed movement would take place at the beginning of the new button hole and in such case it might very frequently happen that a gap would be left at the commencement of the marginal stitches, as is shown in the representation of the stitching illustrated in Figure 12. Owing however to the cam 37 being longer in the present case than the cam 36, the first marginal stitches will lie closer together than the succeeding ones at the beginning of the new buttonhole, as is shown in the upper view of the stitching illustrated by Figure 13. Thus, is obtained a button hole which is faultless on all sides as shown in the lower representation of the stitching in Figure 13.

The mounting of the bell crank lever 29 on the eccentric 33, adjustable by hand, is done for the purpose of enabling the closeness of the stitching to be varied still further than it can be by means of the cams 36 and 37 and, moreover, not only in the case of the stitches of the bar but also in the case of the marginal stitches. In F igures 8 and 9 is shown the normal position of the eccentric 33, while in Figures 10 to 13 it is shown as being rotated through an angle of 90 towards the right. By this rotation the bell crank lever 29 is so moved that the slide 8, together with the crank disc 6 is moved towards the slide-block 11 and the lever arm of the transmitting lever is consequently reduced. The stitches will therefore lie closer against each other, both in the case of the marginal stitches and in the case of the bar stitches than when the eccentric assumes the position shown in Figures 8 and 9. This can also be seen by comparison of the representations of the stitches shown in Figures 8 and 9 with those shown in Figures 10 and 11.

In this way the closeness of the stitches can be made to accord exactly with the various kinds of button holes to be produced, without its being necessary to interchange any parts of the controlling mechanism at all.

I claim:

1. In a button hole sewing machine of that type having a driving shaft and a material feeding mechanism including a cam actuated in step by step movements connections between said driving shaft and said cam including a slide, an oscillatory crank disk journaled in and shiftable with said slide and having a radial slot, a crank connection between the disk and the said driving shaft, a lever having operative connections with the said cam, a block to which said lever is connected movable in said slot of the disk and held against shifting movements of the latter with the slide, and connections for intermittently shifting the slide whereby to adjust the disk relativeto said block.

2. A button hole sewing machine according to claim 1, in which the connections for intermittently shifting the slide include acam in two relatively movable parts, and

4. A button hole sewing machine according to claiml, in which the slide actuating connections include a lever, one end of which engages the slide, and an eccentric forming the fulcrum of said lever whereby it may be bodily shifted for adjusting purposes as described.

In testimony whereof I have signed my name to this specification.

ALBERT I-IENNIG. 

